Endothelial cells apoptosis is one of the main biochemical characteristics of endothelial dysfunction, which is triggered by various stimulations, including high glucose, hypoxia, oxidized low density lipoproteins, oxidative stress and angiotensin II. In vascular endothelial cells, high glucose could accelerate the apoptosis and aggravate the abnormity(Barnes, et al., 2022, Caporali, et al., 2022).
N6-methyladenosine (m6A), the most common RNA chemical modification on posttranscription, could participate in numerous pathophysiological processes(Dhawan, et al., 2022, Ye, et al., 2022). In the vasculopathy, more and more literatures have indicated the essential roles of m6A. For instance, m6A methyltransferase METTL14 plays major roles in TNF-α-induced endothelial cell inflammation through directly targeting m6A modification of important transcription factor FOXO1. METTL14 enhances FIXO1 translation through subsequent YTHDF1 recognition(Jian, et al., 2020). Regarding to m6A methyltransferase METTL3, the silencing or overexpression of METTL3 altered the endothelial cell viability/proliferation/migration/tube formation through regulating Wnt signaling via the m6A modification of target genes (LRP6, DVL1) to enhance the translation of LRP6 and DVL1 in an YTHDF1-dependent manner(Yao, et al., 2020). Collectively, these studies suggest that m6A-mediated modification play an important mechanism in HG-related Vascular pathology.
Here, our work focused on the functions of m6A reader IGF2BP1 on the blood vessel endothelium. We found that IGF2BP1 levels increased upon HG administration. The knockdown of IGF2BP1mitigated the HG-induced apoptosis of HUVECs, besides, IGF2BP1 knockdown renewed the proliferation. Thus, based on our results, we concluded that IGF2BP1 could remarkably regulate the HG-induced vascular pathophysiology.
Given that IGF2BP1 regulated the apoptosis and proliferation of HUVECs, we utilized this discovery to further explore the undergoing mechanism. Interestingly, we found that IGF2BP1 directly bound with the HMGB1 mRNA via m6A modification site. Moreover, IGF2BP1 enhanced the stability of HMGB1 mRNA to up-regulate its protein outcome. In the endothelial cell injury, HMGB1 has been reported to regulate the apoptosis(Zhang and Liu, 2021), inflammation(Foglio, et al., 2022) and autophagy(Feng, et al., 2022) of vascular endothelial cell. Thus, these data suggested the critical roles of HMGB1 in pathological changes of blood vessels.
As the mechanism of the relationship between inflammatory response and atherosclerosis, m6A has become a novel focus in the clinical therapeutic strategy for diabetes mellitus. m6A-dependent post-transcription modification may be a target for diabetes mellitus therapy. Here, we utilized the bio-functional assays to investigate that whether IGF2BP1 and m6A can affect the phenotypic modulation of HUVECs through m6A modification. IGF2BP1 regulates the high glucose-induced vascular endothelial cells apoptosis via m6A/HMGB1 axis by m6A-dependent manner.
Taken together, our data provide robust evidence that IGF2BP1 is an efficient regulator in HG-induced HUVECs. IGF2BP1 and m6A-dependent modification may be one of the primary pathogenesis of vascular pathology and hyperglycemia. These findings strongly support an integral role for m6A in vessel homeostasis and accelerate the high glucose-induced dysfunction of endothelial cells.